Coil-condenser assembly for radio receivers



July 11, 1939. D. P. EARNSHAW COIL-CONDENSERASSEMBLY FOR RADIO HECEIVERS Filed Feb. 27, 1935 3 Sheets-Shes?I 1 July 11, 1939.

D. PA EARNSHAW COIL-CONDENSER ASSEMBLY FOR RADIO RECEIVERS Filed Feb. 27, 1955' 3 Sheets-Shee-t 2 www July l1, 1939.

D, P. EARNSHAW GOIL-CONDENSER ASSEMBLY FOR RADIO REGEIVERS 5 sheets-sheet 3 Filed Feb. 27, 1935 Patented July 11, 1939 UNITED STATES .PATENT OFFICE COIL-CONDENSER ASSEMBLY FOR RADIOv RECEIVERS Application February `27, 1935, Serial No. 8,543

Claims.

rlhis invention relates to a novel coil mounting and to a novel coil-condenser unit for radio receivers, particularly multi-band receivers. In such receivers, the increase in number of coils 5 and condensers presents problems of assembly and these problems are amplified by virtue of the electric-al sensitivity of the particular elements requiring xed electrical characteristics. It is desirable and has been the practice to provide multi-condenser units each having a common base, and multi-coil units 'each having a common support or mandrel. The condenser unit is usually mounted on the shielding can While the coil unit is supported at its lower -ends on the set base. This requires an attachment space at the lower end of the coil unit Where there are mounted the terminals for both units.

With increasingly wide range of multi-band receivers, and consequent increase in condensers and coils, more space for terminals and lead conductors is required. By the present invention, there is provided a novel assembly which provides more space for this purpose and which is extremely compact and results in shortening of the lead conductors, thereby reducing the effect of the lead conductors on the electrical characteristics of the coils and condensers.

The principal object of the invention is, therefore, to provide a novel coil mounting and coilcondenser unit which will fulfill the requirements of the modern radio receiver and which also is easy to manufacture.

The invention may be more clearly understood by reference to the accompanying drawings, in which:

Fig. l is an elevational s'e'ction of the device;

Fig. 2 is a fragmentary elevational View of the upper part `of the coil mandrel;

Fig. 3 is a sectional view along line 3 3 of Fig. 1;

Fig. 4 is a sectional view along line 4-4 of Fig. 3;

Fig. 5 is a fragmentary sectional view along line 5 5 of Fig. 1; Fig. 1;

Fig. 7 is a sectional View along line 'I-l of Fig. 1; and

Fig. 8 is a perspective View of the assembled unit.

Referring particularly to Fig, 1, the preferred form of the invention comprises the coil-condenser assembly I which includes the condenser unit 2 and the coil unit 3. The condenser unit comprises an insulating base 4 carrying the con- Fig. e is a sectional View along line s--sy of denser elements and which is secured Within the shielding can or container 5 to the underside of the top thereof by bolts 6. The non-circular heads 'I of the bolts are seated in correspondingly shaped recesses 8 in the underside of base 5 4, the bolts extending through the base and through the top of the container. Insulating sleeves 9 serve to space the base from the container top the required distance. The spacing may be such that the ends of bolts I6 are just 10 within the container 5 and thus protected from accidental disturbance which might change the adjustment of the condensers I0.

In the specific device illustrated, the condenser unit comprises condensers IU, as shown in Fig. 3. l5 Each of these condensers comprises a stack of plates II., I2 and I3 (see Fig. 4), plate I3 being common to both of the plates II and I2. Plates II and I3 comprise one condenser While plates I2 and I3 comprise a second condenser. Thus 20 each of the condenser units l0 comprises two condensers with a common plate. The plates are each provided with terminal lugs for attachment of conductors. A dielectric plate or plates I4, Which may be formed of mica, separates the 25 plates. The plates may be secured to the base by hollow rivets. Abutments 35 (see Figs. 3 and 5) on the upper surface of base 4 engage the plates I3. The upper surface of base 4 is recessed at 31 and the plates II and I2 have bent 30 portions 38 and 39 respectively which are seated in the recesses 3l, as shown in Figs. 3 and 4. The Walls of the recesses serve as abutments for the plates Il and I2. Thus, the abutments 36 and the abutments formed by recesses 31 serve 35 to retain the plates Il, I2 and I3 in proper alignment. Adjustment devices I5 are provided for the condensers, each comprising a bolt i6 extending through the base and the condenser plates With its head II seated in recess I8 in the 40 base. Each bolt is insulated from the condenser by a 'thick insulating collar I9 and carries an adjustment nut 20 which may be turned by a Wrench inserted through an opening in the can topffAt least one plate of each condenser may 45 be curved slightly to facilitate adjustment and to give Wider range of adjustment. The base may be made of Bakelite, mica mold, or any suitable ceramic material having suitable electrical properties.

The coil unit 3 comprises a coil support or mandrel 2|, which may take the form of an insulating tube which may be of the same material as the condenser base, carrying a plurality of coils 22. The upper end of the mandrel abuts 55 against the under surface of base 4. This surface of the base is provided with arcuate projections or ridges 23 (see Fig. 7) which together with the small arcuate portions 24 of lug 25, also protruding from the base, denne a circular area within which the end of mandrel 2l seats nicely. The lug 25 seats in a recess 26 (see Fig. 2) formed in the end of the mandrel, thereby interlocking the rn-andrel with the base 4 and in proper position relative thereto. The mandrel is secured to the base l b y the transverse or cross bar 2l (see Figs. 1 and 5), which extends transversely cf the mandrel with its reduced ends 28 seated .in T-shaped recesses 2S of diametrically opposed openings 3&1 (see Fig. 2) in the tube wall. A central screw 3l secures the bar to the base 4.

It will be seen that the condenser and coil units, when attached together, form a unitary assembly which may be readily attached to the container. Thus the coil unit is secured at its top by means having excellent insulating properties and this eliminates the necessity of providing an attachment at the bottom of this unit where space is needed for terminal lugs, as has been the practice heretofore. It is important to note also that the upper end of the coil mandrel underlies the heads of the bolts, as shown in Figs. 1 and '7. Thus the bolts are held in place as a part of the assembled coil-condenser unit. This greatly facilitates assembly, especially in quantity production.

Terminal lugs 32 are provided at the lower end of the coil mandrel and, as above stated, a maximum number of these lugs may be provided to accommodate the coils and condensers. Electrical connections to the coils yand some to the condensers may be marde to these terminals. An insulating plate 33 (see Figs. 1 and 6) extends transversely within the container at the bottom thereof and has a central opening to accommodate the coil mandrel. At its central opening, the plate 33 is provided with recesses 34 through which conductors may p-ass. The plate also has openings 35 through which some of the conductors from the condensers may pass. This serves to maintain such conductors in fixed spaced relation to the coils and this will prevent changes in the electrical properties of the unit due to changes in the position of the conductors. The plate 33 also serves to properly space the lower end of the coil unit away from the sides of the container.

It will be seen that the device is compact, permits the use of shorter lead conductors, provides more space for terminals at the bottom of the coil unit, lends itself to quantity production, and has other desirable features and advantages. Furthermore, by holding the coil and conductors in proper spaced relation to the container, minimum coupling between the coil and the container and thus maximum efliciency may be obtained. Furthermore, by mounting the coil form on the insulating base of the condenser, leakage loss may be further reduced. Obviously, changes or modifications may be made within the scope of the invention.

I claim:

1. A shielded coil-condenser assembly for radio receivers and the like, comprising a shielding housing, a condenser unit having an insulating supporting base and condenser elements adjustably mounted on the upper side of said base, attachment elements extending upward through said base and the top of said housing to secure said base to said top, therebeing apertures in s-aid housing top to permit adjustment of said condenser elements, a coil unit having an insulating coil support with an end thereof adjacent the lower side of said base and underlying said attachment elements, and means securing said coil support to said base, thereby said coil support retains said attachment elements in place in said base during assembly.

2. A shielded coil-condenser assembly for radio receivers and the like, comprising a shielding housing, a condenser unit having an insulating supporting base and condenser elements adjustably mounted on the upper side of said base, attachment elements extending through said base and the top of said housing to secure said base to vsaid top, there being apertures in said housing'topto permit adjustment of said condenser elements, a coil unit having an insulating coil support with an end thereof adjacent the lower side of said base and overlying said attachment elements, said coil support having apertures therein adjacent its said end, a cross-bar seated in said apertures, and means securing said crossbar to said base.

3. A radio transformer comprising an insulating core, windings on said core, a ceramic support secured to one end of said core, two tuning condensers mounted on said support and connected to said windings, and a third condenser supported adjacent one of said tuning condensers and having one side in common therewith.

4. A radio transformer comprising an insulating core, windings on said core, a ceramic support secured to one end of said core, abutments formed on the top surface of said support, a stack having condenser plates retained in alignment by said abutments, and means interconnecting said plates whereby a portion thereof forms one condenser and the remainder forms a second condenser.

5. A coil-condenser assembly for radio receivers and the like, comprising an insulating coil support, coils on said support, an insulating condenser support attached to said coil support, a plurality of adjustable condenser units mounted adjacent to one another on said support, at least one of said units comprising a plurality of condensers having a common element, electrical connections between said coils and said condensers, and abutments on said condenser support for retaining said units in position and for retaining the condenser elements of said units in alignment.

DAVID P. EARNSHAW. 

